Abstract:
In this study, a bacterial strain named 206BP, with efficient degradation for the organic matters in shale gas produced water, was isolated from high-salt wastewater and surrounding soil samples. Morphological observation, gram stain and 16S rDNA gene sequence analysis were used to identify the strain 206BP. The results showed that it belonged to the
Bacillus genus as it had 99% similarity with
Bacillus purgationiresistens and other orthologs. The diameter of the strain was about 2.0 μm and the diameter of spore was about 0.3—0.6 μm. Besides, it was confirmed that the strain was gram-positive, capable of producing urease for urealysisand hydrogen sulfide gas as well as hydrolyzing starch and reducing nitrate and nitrite. The growth of the strain 206BP was observed that it stayed at the lag phase in the first 5 h and entered the exponential growth phase in the period of 5—22 h, finally reaching the stationary phase after 24 h. Meanwhile, the effects of NaCl concentration, carbon source, nitrogen source and pH value on the growth characteristics were also investigated. The experimental results showed that the strain 206BP could grow well and was moderately salt-tolerant with NaCl mass fraction of 0—8%. In addition, its optimum growth pH value was in the range of 5—8 and the optimum carbon and nitrogen sources were glucose and urea, respectively. The bacterial concentration in the stationary phase of the growth curve could increase with the concentration of glucose while the stagnation period of the growth curve was prolonged as the glucose concentration exceeded 5 000 mg/L. The added urea had a positive correlation with the strain 206BP growth but the promotion faded away with the urea concentration up to 50 mg/L.